The use of nuclear power is a socio-scientific issue that is controversial in many areas. Concerns of nuclear power touch on health effects, environmental impacts, employment concerns and energy supply; arguments both for and against it are easily generated. This paper examines the specific aspects addressed by preservice primary teachers in their arguments during their participation in a roleplaying activity on the SSI of nuclear power stations closures in Spain. This was done in order to better understand informal reasoning modes, as well as the possible effect of the roles defended and the design of the staging of the role play. To this end, the transcripts of four role plays were analysed. The data analysis was carried out by open coding, extracting different categories of analysis that were classified into three different informal reasoning modes: environmental, financial and social. The results showed that participants used more environmental-oriented arguments than financial and social ones. Differences in informal reasoning modes were found between some roles and between the two parts of the staging. Some educational implications of these results are discussed, such as providing more information to the participants before the roleplaying activity and emphasising the scaffolding of the social aspects when designing the role play.
